Resistance stabilizer for fluid doorchecks



Nov. 26, 1929. H. w. SHONNARD ET AL RESISTANCE STABILIZER FOR FLUID DOOR CHECKS Filed Sept. 14, 1925 2 Sheets-Sheet l Nov. 26, l 929.

H. W. SHONNARD ET AL RESISTANCE STABILIZER FOR FLUID DOOR CHECKS Filed Sept. 14, 1925 2 Sheets-Sheet 2 1 a, I l I l mime 15W Patented Nov. 26, 1929 HAROLD VJ. SHONNARD, OF MONTCLAIR, NEW JERSEY, AND WILLIAM B. CROWELL,

PORATION OF NEW JERSEY N. Y., ASSIGNORS TO ELEVATOR SUPPLIES COMPANY, INC., A COR- RESISTAITCE STABILIZER FOR FLUID DOORGHECKS Application filed September 14, 1925. Serial No. 58,243.

Our present invention relates to a novel arrangement of apparatus for use in connection with elevators employing self-closing doors, whereby a constant resisting force may be maintained at all times in all of the automatic door checking apparatus at the various floors in one or more shafts.

Our invention is illustrated in a preferred form in the accompanying drawings wherein Figure 1 is a diagrammatic view of the invention, showing a portion of a single elevator shaft and car, Figure 2 is a view in elevation of the pressure reservoir showing the emergency oil valve in detail, and r igure 3 is a sectional view of one form of door check which may be used with our invention.

In Figure 1 is shown the general construction used at the upper part of an elevator shaft, two floor positions being illustrated it being understood that, except for the reservoir and emergency valve, the construction is substantially duplicated at the various floors below the top. lVe shall first describe the structure already in use as here illustrated and, after explaining the disadvantages which have to be overcome in such structures, we shall make clear the substance of the present invention and the mode in which it overcomes these disadvantages.

At is shown one of the stationary sliding doors provided on each fioor, which may be opened and closed by the piston rod 11 or a pneumatic engine 12 attached to a togglebar system 13 for moving the door or doors in a well known manner. In opening the door compressed air is supplied to the cylinder 12 by means of a pipe 14, passing from the valve 15 connected with the general supply p pe for compressed air shown at 16. Thls valve is operated by the movable member 17 of an automatic valve operator on the car 18, which may be made to press the valve operating lever 19 at will. The supply of air, on its way to the cylinder 12, preferably passes through the expansion chamber 20, as fully described in an earlier application for patent filed by us. It is not essential to the present invention.

To close the door or doors 10, the comair is permitted to exhaust to atmosphere, and a spring within the cylinder 12 (notshown) operates to close the door.

In order to bring the door to a standstill at the end of its movement in both directions a by-pass fluid door check (preferably employing oil) is employed at the lower end 21 of the cylinder 12. This door check comprises a plunger on an extension of the piston rod passing through a suitable partition across the cylinder 12 into a dash pot chamber filled with oil, which is allowed to pass from one side of the dash pot plunger to the other through adjustable needle valves, thus producing the checking effect desired. The construction so far described is all old and details have therefore not been illustrated. The parts 10, 12, 13, 15, 19, 20, 21 at the upper floor are indicated by the numerals 10, 12, 13, 15, 19', 20, 21 at the lower floor.

The design in constructing a door check of this character is to provide a dash pot and communicating passages completely filled with oil, which will produce a constant predetermined degree of retardation which can be regulated by the needle valves.

In practice, however, it has been found that there is an unavoidable slow loss of oil whereby space is left within under pressure finds its way through the stulfing box from the cylinder into the dash pot, and the foreseen conditions governing the original setting of the needle valve regulators are seriously disturbed, with the result that there is more or less slamming at the end of each movement of the door.

This difficulty cannot be obviated'practically by a resetting of the needle valves; first, because it would require almost constant regulation of the numerous door checks on many floors and in a number of shafts; and second, because the extent of distribution of balance varies with the amount of use of the engine 12. This arises from the fact that the pres sure acting to force air into the dash pot varies constantly from about that of the atmosphere (when the springs acts to close the door) to full active air pressure (usually about seventy pounds to the square inch) when the engine 18 opening the door. Therethe dash pot. Air

'mosphere, and the checking action is insufficient to prevent slamming. This periodic variation is additional to that caused by the constantly diminishing volume of oil in each dash pot.

In order to entirely eliminate these difficulties and to secure the ideal of a dash pot always completely filled with oil, with consequent uniform checking resistance, our pres ent invention consists in the employment of an nternal oil reservoir connected with the dash pot by suitable piping, and so arranged as to supply new oil to the dash pot at all times to compensate for that which is lost by leakage, evaporation or other causes. The door check is used as above described in combination with a compressed air engine, and we prefer to place the fluid (oil) within the supply reservoir under the same degree of air pressure as is used to operate the engine. Of course, a separate reservoir might be employed for eachdoor check, but in elevator systems it is best for obvious reasons to supply a single general reservoir, either for all the doors in each shaft or for all the doors in all the shafts.

In-the drawing the oil supply reservoir is shown at 22 which is connected to a pipe 23 which extends the whole length of the shaft, being tapped off at each floor by a branch pipe 2 leading to the dash pot or dash pots 21 at that particular floor. As shown in Figure 2, the pipe 23 extends down to near the bottom of the reservoir, so as to open well below the level of fluid in the same.

From the general supply pipe for compressed air 16 a pipe 25 leads into the top of the reservoir 22, so that the fluid is always under the pressure that operates the door openers. In this manner no aircan find its way into the dash pots, and they remain constantly full of oil.

We prefer to supply an automatic emergency or safety valve 26 in the pipe 23, preferably placed close to the reservoir 22, as shown. This valve contains av ball 27-, Which rests on a support 28 during the normal slow seepage of fluid outward. In case of a break anywhere in the piping 23, 24:, however, the sudden momentary rush of fluid through 23 under the influence of the high air pressure, forces the ball 27 into the opening 29 and effectually prevents loss of oil and air.

Many changes might be made in the system as herein set forth without departingfrom the scope of our invention, which is not limited to the details herein shown and described.

What we claim is 1. In an elevator system having a plurality of doors one over the other, a pneumatic door opener for each door a compressed air supply pipe extending past all of said door openers and communicating operatively with each of said openers, an oil operated check for each door, an oil reservoir, a pipe connected between the air supply pipe and said reservoir, a common oil supply pipe extending past all 'of the door checks and communicating with said reservoir, and branch pipes leading from said common oil pipe to the separate door checks in the system.

2. In an elevator system having a plurality of doors, a pneumatic door opener for each door, a dash-pot for each door opener, a reservoir adapted to supply fluid to all of said dash-pots and means for maintaining over the fluid supply in the reservoir a gaseous pressure higher than that of the atmosphere.

3. In an elevator system, a plurality of doors each provided with a fluid operated door check, a common reservoir of fluid connected with all of said checks to compensate for leakage, a source of compressed a r, and

means for admitting said compressed air to he surface of the fluid in the reservoir.

4. Apparatus as in claim 8 in combination with a safety check valve in the fluid exit from the reservoir, adapted to be closed by any sudden rush of fluid from the reservoir.

In testimony whereof we have hereto affixed our signatures on this 8th day of September, 1925. 1

HAROLD W. SHONNARI). WVILLIAM B. CRONELL. 

